Study on Dynamics of Luminous Environment in Architectural Space in the Daytime: Part 2. Daylit Environment in Office Space

The goal of this research work is to get an advanced knowledge of the real dynamic state of the luminous environment in the daylit architectural space. For this purpose, measurements have been done in actual architectural spaces, for instance, a house and an office space under various sky and weather conditions. And many useful suggestions have been obtained from the results of analyses of the data gained. This paper reports the results of a study on a daylit environment in office space. The following important conclusions were obtained. 1) Independent of sky and weather conditions, the diurnal fluctuation of the horizontal illuminance, the illumination vector, the scalar illuminance, and the cylindrical illuminance at the same position in a daylit room were similar when no direct sunlight entered the interior. This suggests the possibility of estimating the values and the diurnal fluctuations of the illumination vector, the scalar illuminance, and the cylindrical illuminance in daylit rooms from the horizontal illuminance. 2) From the viewpoint of modelling and silhouette phenomenon, the quality of the luminous environment of interiors generally deteriorated when the luminous environment of interiors was lit only by daylight. 3) Generally, the quality of the interior luminous environment could be improved by using supplementary artificial lighting. 4) There is a danger of excessive amount of artificial light harming modelling conditions.